polygon generator

main.dart

import 'dart:math';

// -----------------------------------
// -----------------------------------
// These are the values that you will want to adjust before hitting run.

// Take note that this is in a lat/long order (what you would normally get from Google Maps, etc)
const centerPoint = [39.1094384, -84.5094552];

// 1 mile
const radiusInMeters = 1609.34;

// a hexagon has 6 sidees
const serviceAreaSides = 6;

// If you wanted a flat top, use "360 / serviceAreaSides" as the value
const serviceAreaRotationDeg = 360 / serviceAreaSides;
// -----------------------------------
// -----------------------------------

// Don't try to land a rocket based on this math (favors simplicity over accuracy)
// https://stackoverflow.com/a/50506609
const earthRadiusInMeters = 6378137.0;
const degreesPerRadians = pi / 180.0;
const radiansPerDegress = 180 / pi;
const metersPerDegree = (1 / ((2 * pi / 360) * earthRadiusInMeters));

void main() {
  var centerLat = centerPoint[0];
  var centerLong = centerPoint[1];

  var points = [];
  for (var i = 0; i < serviceAreaSides; i++) {
    var pointOffsetDegrees =
        serviceAreaRotationDeg + ((360 / serviceAreaSides) * i);

    var dNorthMeters =
        radiusInMeters * sin(pointOffsetDegrees * degreesPerRadians);
    var dEastMeters =
        radiusInMeters * cos(pointOffsetDegrees * degreesPerRadians);

    var adjustedLat = centerLat + (dNorthMeters * metersPerDegree);
    var adjustedLong = centerLong +
        (dEastMeters * metersPerDegree) / cos(centerLat * (pi / 180));

    points.add([adjustedLat, adjustedLong]);
  }

  points.add(points[0]);

  for (var i = 0; i < points.length; i++) {
    var trailing = ((i + 1) == points.length) ? '' : ',';
    print('[${points[i][1]}, ${points[i][0]}]${trailing}');  // long,lat...argh
  }
}